In the art of ion-exchange reaction with the use of a resin, the batch process is inefficient and therefore recourse is made more frequently to the continuous columnar process (fixed bed ion-exchange system). However, the columnar process involves some drawbacks. One is that a large amount of a resin must be used. In addition, because of insufficient contact of the resins with the feed solution, the apparatus must have a complicated structure to cause sufficient contact with the feed solution. Thus, the columnar process is not suitable for application in treatment of a small quantity of feed solution. Accordingly, it is preferable to adopt the batch process in order to reliably collect lysozyme by adsorption at low cost, which lysozyme is contained only in a quantity of about 0.3% in egg white. In the case of the batch process, however, there is the problem of inefficiency as mentioned above involving, for example, cumbersome operations such as delivery of resins or feed solution from the adsorption tank to another tank. For solving this problem, employment of pressurized air for stirring or delivery of resins or treated solution has been investigated, but this attempt has proved to result in increase of the cost. In conclusion, under the present state of the art, no suitable device in either columnar or batch system has been developed for adsorbing or extracting lysozyme economically by treatment of a small amount of the egg white starting material.
In view of the background as described above, we have made studies to develop an apparatus for collecting by adsorption lysozyme in egg white which is convenient for use with easy handling, efficient, suitable for a small-quantity treatment and yet inexpensive. Especially we have placed emphasis on the two points that the adsorption tank of lysozyme should be made to have a construction such that it can be used as it is as the lysozyme extraction tank and that delivery of resins or solutions should be performed by a mechanism without the need of pressurized air. Thus, starting with a study on the quantities of resins required, followed by various tests, the apparatus according to the present invention has been reduced to practice.